This invention relates generally to a liquid dispenser, and more particularly to a piston-type positive displacement applicator capable of dispensing high viscosity sealants, for example, in repeatable and controlled quantities to facilitate the coating, for example, of workpieces such as threaded pipe fittings.
Sealants, especially of the high viscosity type, are oftentimes difficult to dispense in an accurate and controlled manner particularly when coating cylindrical workpieces. It is desirable to coat, for example, the threads of pipe fittings only with optimum amounts of sealant during repeatable applications of the same or differently sized fittings. Excessive amounts are wasteful and give a sloppy appearance while insufficient amounts could affect the sealing quality. Moreover, the dispensing should be carried out quickly without compromising on accuracy.